Novel Preparation of 6-O-Acyl Chlorosucrose from Anhydrous Cholorinated Reaction Mass

Abstract

A process is described for production of a chlorinated sucrose from a process stream containing a 6-O-protected chlorinated sucrose derived from chlorination of 6-O-protected sucrose wherein the process stream is treated under conditions which prevent or reverse deacylation of 6-O-protected chlorinated sucrose, extracting the same in a solvent, washing most of the dimethylformamide free from the solvent extract by repeated washing with saturated sodium chloride solution, isolating the 6-O-protected sucrose as a pure fraction and obtaining a chlorinated sucrose by deacylating the same.

1 - 4 . (canceled) 
     
     
         5 . A process of production of a chlorinated sucrose from a process stream comprising purification of 6-O-protected chlorinated sucrose from a solution and its subsequent deacylation and isolation of the chlorinated sucrose wherein the said solution is substantially anhydrous and the said process comprising one or more of following steps:
 a. an acidic process stream containing 6-O-protected sucrose having pH below 5 is neutralized under anhydrous condition by a mild alkali preventing the pH to go beyond 7, more preferably between 5 to 6,   b. preferably chlorinated sucrose formed in a process prior to purification of the said anhydrous solution of 6-O-protected chlorinated sucrose, including a process of neutralization of an acidic solution having pH below 5, is acylated by treating with an acylating agent to produce 6-acyl chlorinated sucrose.   
     
     
         6 . A process of  claim 5  wherein
 a. the said chlorinated sucrose compound comprises a chlorinated sucrose including trichlorogalacrosucrose, a dichlorosucrose, a tetrachlorosucrose and the like,   b. the said chlorination reaction comprises reacting sucrose or sucrose derivative with one or more of a chlorinating reagent by one or more of a process including:
 i. a reaction of sucrose dissolved in pyridine with sulphuryl chloride, or 
 ii. a reaction of sucrose with thionyl chloride in a nitrogenous base of free hydroxyl and in presence of non-reactive moderately polar organic solvent, or 
 iii. a reaction of a 6-O-protected sucrose with a Vilsmeier reagent of a general formula [HCIC=N.sup.+R.sub.2]CI.sup.-, or [HPOCI.sub.2.O.C.sup+=N.sup+.R.sub.2]CI.sup.-, where R represents an alkyl group preferably a methyl or ethyl group, 
   c. the said mild alkali comprises one or more of an alkali which shall not lead to increase in pH above 7 when added to a solution, including ammonia, preferably in a gaseous form, and the like,   d. the said acylating agent includes acetic anhydride and the like,   e. the said purification of 6-O-protected chlorinated sucrose is preferably done by extraction in a solvent capable of extracting 6-O-protected chlorinated sucrose comprises use of one or more of a partly miscible or immiscible organic solvent including ethyl acetate, butyl acetate, methyl ethyl ketone, methylene dichloride, ethylene dichloride, toluene, and the like,   f. 6-O-protected chlorinated sucrose extracted in one or more of a partly miscible or immiscible organic solvent, is preferably washed with saturated salt solution, preferably a sodium chloride solution to remove dimethylformamide.   
     
     
         7 . A process of  claim 6  comprising steps of:
 a. sparging ammonia gas, as a mild alkali, under anhydrous condition by bubbling through the process stream obtained after a chlorination reaction to achieve its neutralization maintaining pH of the process stream to around 5.8 throughout the neutralization process, preferably with an optional addition of an ammonium acetate buffer,   b. cooling to around 0 degrees celcius and adding acetic anhydride in a quantity and allowing acetylation to occur for a period of time enough to acetylate back most of the TGS formed in the process stream until the end of step (a.) of this claim,   c. terminating the acetylation reaction, preferably by adding demineralized water in 1:1 proportion,   d. extracting 6-O-protected TGS from process stream of step (b.) of this claim by extraction in a solvent, preferably ethyl acetate, and   e. isolating 6-O-protected TGS from the process stream of step (d.) of this claim free from one or more of other extracted constituents by a step of purification and isolation.   
     
     
         8 . A process of  claim 7  where the said purification in step (d.) comprises removal of dimethylformamide, abbreviated as DMF, by one or more of a step of its removal including repeated washing by saturated salt solution, preferably a sodium chloride solution, until level of DMF in the Process Stream decreases significantly, preferably up to 0.5% or less.